A dose-ranging study evaluating the oral factor Xa inhibitor edoxaban for the prevention of venous thromboembolism in patients undergoing total knee arthroplasty

Background: Edoxaban (the free base of DU-176b) is an oral, direct factor (F)Xa inhibitor in clinical development for the prevention and treatment of thromboembolic events. Objectives: The aim of the present study was to evaluate the efficacy and safety of edoxaban for the prevention of venous thromboembolism (VTE) in patients undergoing total knee arthroplasty (TKA). Patients/methods: This was a randomized, double-blind, placebo-controlled, multicenter study conducted in Japan. A total of 523 Japanese patients were assigned to receive edoxaban 5, 15, 30 or 60 mg once daily or placebo for 11-14 days. A placebo control was used as neither low-molecular-weight heparin (LMWH) nor fondaparinux had been approved for thromboprophylaxis at the time of the study in Japan. The primary efficacy outcome was the incidence of VTE (lower-extremity deep vein thrombosis, symptomatic pulmonary embolism or symptomatic deep vein thrombosis). The primary safety outcome was the incidence of major and clinically relevant non-major bleeding. Results: Edoxaban produced a significant dose-related reduction in VTE: the incidence of VTE was 29.5%, 26.1%, 12.5% and 9.1% in the edoxaban 5-, 15-, 30- and 60-mg treatment groups vs. 48.3% in the placebo group. The incidence of major and clinically relevant non-major bleeding was similar across all groups without any significant differences among edoxaban doses or between edoxaban and placebo. Conclusions: Edoxaban demonstrated significant dose-dependent reductions in VTE in patients undergoing TKA with a bleeding incidence similar to placebo. [This trial is registered with JAPIC, JapicCTI-060283 (ja).].